Researchers create "MRI" of the Sun's interior motions

Oct 03, 2012 by James Devitt
Image of sun courtesy of NASA.

(Phys.org)—A team of scientists has created an "MRI" of the sun's interior plasma motions, shedding light on how it transfers heat from its deep interior to its surface. The result, which appeared in the journal the Proceedings of the National Academy of Sciences, upends our understanding of how heat is transported outwards by the sun and challenges existing explanations of the formation of sun spots and magnetic field generation.

The work was conducted by researchers from NYU's Courant Institute of Mathematical Sciences and its Department of Physics, Princeton University, the Max Planck Institute, and .

The sun's heat, generated by in its core, is transported to the surface by in the outer third. However, our understanding of this process is largely theoretical—the sun is opaque, so convection cannot be directly observed. As a result, theories largely rest on what we know about and then applying them to the sun, which is primarily composed of hydrogen, helium, and plasma.

Developing a more precise grasp of convection is vital to comprehending a range of phenomena, including the formation of sun spots, which have a lower temperature than the rest of the sun's surface, and the sun's magnetic field, which is created by its interior plasma motions.

In order to develop their "MRI" of the sun's plasma flows, the researchers examined high-resolution images of the sun's surface taken by the Helioseismic and Magnetic Imager (HMI) onboard NASA's Solar Dynamics Observatory. Using a 16-million pixel camera, HMI measures motions on the sun's surface caused by convection.

Once the scientists captured the precise movement waves on the sun's surface, they were able to calculate its unseen plasma motions.

What they found significantly departed from existing theory—specifically, the speed of the sun's plasma motions were approximately 100 times slower than scientists had previously projected.

"Our current theoretical understanding of magnetic field generation in the sun relies on these motions being of a certain magnitude," explains Shravan Hanasoge, a research scholar at Princeton University and a visiting scholar at NYU's Courant Institute of . "These convective motions are currently believed to prop up large-scale circulations in the outer third of the sun that generate magnetic fields."

"However, our results suggest that convective motions in the sun are nearly 100 times smaller than these current theoretical expectations," continued Hanasoge, also a postdoctoral fellow at the Max Planck Institute in Katlenburg-Lindau, Germany. "If these are indeed that slow in the sun, then the most widely accepted theory concerning the generation of solar magnetic field is broken, leaving us with no compelling theory to explain its generation of magnetic fields and the need to overhaul our understanding of the physics of the sun's interior."

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User comments : 4

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cantdrive85
1 / 5 (4) Oct 03, 2012
The 'Electric Star' model has no such problems, the observations still support this theory. It answers the EM field questions, CME's, solar wind, hot corona, and the neutrino deficit, it's only a matter of time now.
MrGrynch
1 / 5 (4) Oct 03, 2012
enter Plasma Cosmology. Maybe the magnetic fields are not generated like a dynamo at all but rather from external Birkeland currents feeding the Sun. These currents would generate their own magnetic field. This discovery may be an opening for mainstream scientists to look in this direction.
rubberman
1.5 / 5 (2) Oct 03, 2012
Piece by piece, from all of the articles i have been reading here and on other sites lately, it appears astrophysicists are on the way to a hybrid theory where plasma cosmology plays a signifigantly larger roll in explaining the phenomena we are seeing.

I wonder, when a viable working one is proposed, if the rest of the room will all hold up white cards rating him 1 star out of 5. As our understanding increases, it appears to be getting more difficult to shoehorn the observations into the classical theories.
GSwift7
5 / 5 (1) Oct 04, 2012
The 'Electric Star' model has no such problems


This discovery may be an opening for mainstream scientists to look in this direction


Unfortunately, you really don't know what you are talking about. The electric/plasma nature of the sun is undisputed in mainstream science. On the scale of a star, there's no reluctance in mainstream science to accept it's electrical properties.

Mainstream science only starts to dismiss the electric universe theories when you try to take them to scales larger than the solar system.

In fact, when you suggest that the above story helps support the electric universe theories, that is the opposite of what it said. They seem to have found that the electrical properties of the sun may not be as strong as they thought.

I think the answer to the problems indicated by the above observations is most likely to be a problem with the method of observation, rather than a hole in the theories.